Researchers found the same amount of tumor cells present at surgery among women:

treated before surgery with trastuzumab (Herceptin) plus paclitaxel (Taxol), followed by anthracycline chemotherapy

receiving the same treatment, but with more trastuzumab given at the same time as the anthracycline

This finding from a phase III trial supports past studies showing trastuzumab is not needed during anthracycline (e.g., doxorubicin or epirubicin) treatment to shrink or get rid of the cancer before surgery.

Background and Goals

Researchers know adding trastuzumab to chemotherapy after surgery lowers the risk of breast cancer returning. They also know neoadjuvant chemotherapy, given before surgery, can shrink tumors. This makes them easier to remove and may lead to better survival rates.

Results of other phase III treatment studies involving people with HER2-positive breast cancer showed disease-free survival, DFS, and pathologic complete response, pCR, both improve when trastuzumab is added to anthracycline-based chemotherapy, such as FEC-75 followed by paclitaxel. Still, doctors don’t know if giving trastuzumab at the same time as an anthracycline chemotherapy regimen like this one adds benefit.

FEC-75 is the name of a group of chemotherapies that includes the medicines fluorouracil, epirubicin (an anthracycline) and cyclophosphamide combined. DFS is the length of time there is no evidence of cancer, and pCR is no evidence of cancer at the time of surgery.

Today, most providers do not give trastuzumab during the anthracycline part of the treatment because of concern that both medicines can hurt the heart. Giving them on the same day might cause more heart problems.

The trial team explored whether giving trastuzumab at the same time as FEC-75 was necessary, rather than just during the paclitaxel part of the treatment. They did this by comparing rates of pCR among treatment groups.

Design

The research team enrolled 280 adult women with HER2-positive breast cancer. They were randomly assigned to one of two treatment groups:

FEC-75 alone, given by vein for 4 cycles, followed by paclitaxel plus trastuzumab for 4 cycles

Paclitaxel plus trastuzumab for 4 cycles, followed by FEC-75 together with trastuzumab for 4 cycles

Before starting their trial treatment, each woman had baseline measurements taken of cancer in the breast and lymph nodes. All women also had a physical exam and blood tests done at the beginning of each new treatment cycle to check the tumor size and assess side effects. Doctors tested heart health at 12 and 24 weeks.

After finishing the trial treatment, each participant had a mammogram, surgery, and post-surgery treatment as recommended by their doctor. The trial team followed participants for up to 5 years.

Results

After 5 years, researchers found both groups had the same rate of pCR. This means taking trastuzumab at the same time as FEC-75 was not more effective than taking FEC-75 alone, when trastuzumab is also given with the paclitaxel part of the treatment.

Data also confirms an excellent rate of pCR in HER2-positive breast cancer when women are given pre-surgery treatment with a taxane (paclitaxel), an anthracycline, and trastuzumab.

Regular heart-health check-ups showed the two treatment groups had roughly the same low number of women with heart-related side effects. This means the treatments may be equally safe, but further study is needed to confirm the finding since heart-health follow-up was not long-term.

What This Means for You

In this study, a group of women given trastuzumab only at the same time as half of their pre-surgery chemotherapy had the same high rate of pCR as another group given twice as much trastuzumab overall. This shows adding more than the current standard amount of trastuzumab before surgery doesn’t seem to lessen the amount of cancer found at the time of surgery. By limiting the amount given, side effects can be kept to a minimum.

Instead, many women with HER2-positive breast cancer getting chemotherapy before surgery are now given both trastuzumab and pertuzumab based on other studies showing a benefit to the pair. In general, these medicines are only given during the taxane part of chemotherapy, not when the anthracycline is given.

Researchers are still studying the use of pre-surgery treatment, but trials like these are helping expand doctors’ knowledge of how these methods may improve survival in the future.

If you are interested in neoadjuvant treatment, talk with your doctor to learn more, or visit clinicaltrials.gov to see if you are eligible for studies like this.